Numerical Simulation of the Flow in a Kaplan Turbine Model during Transient Operation from the Best Efficiency Point to Part Load

Iovănel, Raluca Gabriela; Dunca, Georgiana; Bucur, Diana Maria; Cervantes, Michel

doi:10.3390/en13123129

Cited by 15 publications

(16 citation statements)

References 35 publications

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“…A comparative time-step sensitivity study on the Francis-99 model complete turbine domain and turbine with passage domain were performed by Sotoudeh et al [19]. A similar time-step sensitivity study was performed by Iovanel et al [20] on the Kaplan turbine numerical model with one guide vane passage domain and a complete runner-draft tube domain. The results of both studies confirmed that with larger time-step and reduce geometry modeling, the RVR frequency was captured accurately.…”

Section: Authorsmentioning

confidence: 99%

“…However, the amplitude of the RVR frequency largely depends on the time-step considered. More specifically, for smaller time-steps, larger RVR amplitude was observed and vice versa [20]. A literature review on numerical techniques applied to hydro-turbines done by Trivedi et al [3] concluded that it still is quite challenging to obtain an accurate prediction of pressure amplitudes in the hydro-turbines, especially with RANS turbulence models.…”

Section: Authorsmentioning

confidence: 99%

“…To save computational time, a time step of the runner rotation of 24º (one runner passage) + 1º was considered in the present study [19]. The effects of such time step have previously been investigated by Iovanel et al [20]. A high-resolution advection scheme and second-order backward Euler transient scheme was specified in the present numerical study to solve the continuity and momentum equations.…”

Section: Francis-99 Reduced Modelmentioning

confidence: 99%

“…al. [20]. When large time-steps are considered in numerical modeling of hydro-turbines, the amplitudes of the corresponding frequencies are relatively lower.…”

Section: Analysis Of Pressure Pulsations and Rvr Frequencymentioning

confidence: 99%

“…Table 1 Summary of numerical analysis performed on hydro-turbines. Several validation studies of the experimental data have been performed in the past using CFD tools on hydro-turbines [7][8][9][11][12][13][14][15][16][17][18][19][20]. A summary of numerical studies performed on hydro-turbines are presented in Table 1.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Reduced Numerical Modeling of a High Head Francis Turbine Draft Tube at Part Load

Joy¹,

Cervantes²,

Raisee³

2021

IJFMS

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In the present study, a reduced model of the Francis-99 model turbine was investigated numerically at part load operating condition. The reduced model consists of a standalone draft tube domain of the Francis-99 model turbine. Numerical studies performed in the past on nearly complete hydro-turbine models (inclusive of the spiral casing, distributor domains, runner, and draft tube) reportedly consist of a large number of computational grids. This may increase the computational costs and data storage required to perform numerical analysis, which could be a setback for future research on new design concepts and optimization study of the draft tube domain. The reduced model was developed by mapping the phase averaged axial, radial, and tangential velocity profiles from the runner exit to the inlet of the standalone draft tube domain. Additionally, turbulent kinetic energy (k) and turbulent eddy dissipation (ε) variables were also considered for better flow prediction inside the draft tube domain. Two methods for mapping inlet boundary conditions were considered in the present study. In the first method, the entire planar profile of the runner-draft tube interface was considered. In the second method, the variables along a radial profile at the runner exit were considered with an axissymmetric flow assumption over the entire draft tube inlet plane. The numerical results obtained from the Francis-99 reduced model turbine were validated against the numerical model of the NVKS Francis-99 model turbine (with available structured mesh) that was also analysed using the passage flow numerical technique and available experimental results. The results were found to be in reasonable agreement, with each other. The present study could be useful for the future mitigation study of rotating vortex rope by modifying the draft tube domain.

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Section: Authorsmentioning

confidence: 99%

Section: Authorsmentioning

confidence: 99%

Section: Francis-99 Reduced Modelmentioning

confidence: 99%

“…al. [20]. When large time-steps are considered in numerical modeling of hydro-turbines, the amplitudes of the corresponding frequencies are relatively lower.…”

Section: Analysis Of Pressure Pulsations and Rvr Frequencymentioning

confidence: 99%